Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Orthodontics

Objectives: This study was carried out to investigate clinically and using CBCT imaging the prevalence of transverse malocclusion in a sample of subjects with different signs and symptoms of TMD and to study the morphological and positional characteristics of the mandibular fossae and condyles as well as the condyle-fossa relationship. Furthermore, to correlate the transverse occlusion and transverse skeletal discrepancy, with the clinical findings of TMD, and the CBCT measurements of the TMJ . Materials and methods: A sample of one hundred and fifty TMD patients participated in the present study. Clinical examination of the transverse occlusion was carried out. History taking and clinical examination was performed as recommended by DC/TMD(48) (Appendix II) for every patient. The total sample was divided into five groups based on the diagnosis according to DC/TMD. Each patient was imaged using CBCT utilizing the next generation i-CAT® machine, and a standardized stepwise innovative 3D temporomandibular joint analysis, was performed by using the Anatomage® software version 5.01. A comprehensive transverse CBCT analysis was carried out to evaluate several craniofacial and dental transverse features. Assessment of the mandibular fossa and condyles, TMJ spaces and intrajoint condylar positions was also performed for each patient in the five TMD groups. All linear and angular measurements were performed on 3D volumetric images with the help of the multiplanar slice locator. Results & Conclusions: Normal posterior transverse occlusion was found in 82% of the total sample. Posterior crossbite was found in only 18% of the sample, distributed as follows; True bilateral crossbite and unilateral functional crossbite were each found in 6% of the sample. Four percent had a true unilateral crossbite, and only 2% showed buccal crossbite. Temporomandibular joint spaces and the intra-joint condylar positions showed significant differences among the different TMD categories. Patients diagnosed with TMJ disc displacement, whether with or without reduction, showed significantly smaller superior and posterior joint spaces, and more posteriorly positioned condyles, compared with the myalgia group which showed more anteriorly positioned condyles

Issued also as CD